Sorry I can't be of actual help on this, but there is a wonderful DVD that I have called Boxes and Bows by Sharon Zambito. You can find it at sugaredproductions.com. She has one were the lid is propped open. The instructions are thorough and wonderful and the best part is, it is right there and you can pause as you need. I would really recommend it!

Lid: gumpaste and fondant (I usually mix 50/50) cut square, shape it on the bottom of thecake pan that will be used for the box. Spray the bottom pan with cooking spray before placing the gumpaste/fondant. Let it dry overnight.

Tissue paper: roll thinly the gumpaste, cut into squares, similar sizes. Arrange to dry on the top of crumple saran wrap in different shape, i.e. folded, frilled, etc.

I just want to add, that I haven't bought Sharon's boxes and bows DVD, but planning to order it.I have bought her butter-cream and fondant DVD, and highly recommend them. The instruction is very detailed!

Sharon's DVD is very good and it is worth buying, but if you need some instructions on making a box cake you could check this video by Expert village on You Tube. It has several parts starting with this link.